Pure fluid push-pull summing amplifier of the impact type



Feb. 11, 1969 s. A. GRAY 3,426,780

PURE FLUID PUSH-PULL SUMMING AMPLIFIER OF THE IMPACT TYPE Filed Sept.16, 1966 SAMUEL ,4. GQAY ILL ii INVENTOR FE G. 3 fiwflaw 5x40249 40ATTORNEYS- United States Patent 3,426,780 PURE FLUID PUSH-PULL SUMMINGAMPLIFIER OF THE IMPACT TYPE Samuel A. Gray, Sun Valley, Calif.,assignor to Bell Aerospace Corporation, a corporation of DelawareContinuation-impart of application Ser. No. 562,338, July 1, 1966. Thisapplication Sept. 16, 1966, Ser. No. 579,973 US. Cl. 137-815 12 ClaimsInt. Cl. FlSc 1/14 ABSTRACT OF THE DISCLOSURE Disclosed is a fluidicamplifier which utilizes the impact type proportional amplifierprinciple, both direct and transverse, to provide a push-pull outputsignal which is proportional to the difference between the momentum fluxof the impacting input streams.

This invention relates generally to pure fluid amplifiers and moreparticularly to a push-pull proportional summing amplifier whichutilizes the impact technique.

This application is a continuation in part of United States patentapplication, Ser. No. 562,338, now abandoned, filed July 1, 1966 bySamuel A. Gray for Pure Fluid Push-Pull Summing Amplifier of the ImpactType.

Pure fluid amplifier type devices have become rather well known in thepast few years. In such devices there are no moving parts other than thefluid (i.e. the gas or liquid which flows therethrough) and thereforethere is nothing in the device to wear out. The devices themselves canbe manufactured of any material which is desired including plastic,metal and ceramic. Therefore, temperature is not a limiting factor as isthe case in many active devices utilized for amplification. As a resultof the foregoing, fluid amplifiers have potential for wide applicationin various fields, primarily as a result of their high reliability,their temperature insensitivity, their shock resistance and their easeof fabrication. Fluid amplifiers as presently recognized in the priorart may be operated as pneumatic devices employing a compressible fluidsuch as gas or air, or as hydraulic devices utilizing an incompressiblefluid such as water or oil. The pure fluid amplifiers at present fallinto two basic types. These types are either of the on-off logic type orof the proportional amplifier type device. The present invention isdirected specifically to the proportional fluid amplifier.

Various pure fluid devices and particularly of the proportionalamplifier types are well known in the prior art, for example, such asthe stream interaction amplifier, the double-leg elbow amplifier, thevortex amplifier, and the impact modulator. Such devices, among others,are described and illustrated in Machine Design, June 24, 1965 issue,pages 154 through 180. The present invention more specifically utilizesthe techniques and principles employed in the impact modular typeamplifier.

In the impact modulator type proportional amplifier a pair of collinearpower input tubes are arranged to cause axially opposing jets of fluidto impact. Such impact causes the production of a radial jet, theposition of which is determined by the relative strength of the twoimpacting jets. The relative strength of the two jets may be varied bydirectly changing the pressure of the impacting jets or by introducinganother jet transversely to the axis of the impacting jets. In eitherevent the sensed pressure in the output chamber changes according to theposition taken by the radial jet. All presently known impact modulatortype amplifiers are single ended. Thus to interface with any push-pulltype device requires two such amplifiers properly interconnected toprovide the necessary output signals.

Accordingly, it is an object of the present invention to provide apush-pull fluid amplifier having no moving parts.

It is another object of the present invention to provide a fluidamplifier which is simple, rugged and easy to manufacture.

It is a further object of the present invention to provide a novel fluidamplifier utilizing the impact technique to produce a push-pull outputsignal.

It is still a further object of the present invention to provide a novelfluid amplifier using the impact technique which provides an improvedgain, a higher sensitivity, and a greater efficiency.

Additional objects and advantages of the present invention both as toits operation and organization will become apparent from a considerationof the following description taken in conjunction with the accompanyingdrawing which is presented by way of example only and is not intended asa limitation upon the scope of the claims appended hereto and in which:

FIGURE 1 is a perspective view of a device constructed in accordancewith the present invention;

FIGURE 2 is a schematic representation of a pushpull amplifier inaccordance with the present invention, when the signals applied theretoare equal;

FIGURES 3 and 4 illustrate the device shown in FIG- URE 2 with the inputsignals applied thereto having different relative magnitudes; and

FIGURE 5 is a schematic representation of an alternative embodiment of apush-pull amplifier in accordance with the present invention.

A pure fluid push-pull summing amplifier in accordance with the presentinvention includes a pair of axially aligned input nozzles arranged tohave fluid emanate therefrom in such a manner so as to impact along apredetermined axis in such a manner as to form a radial jet. There isarranged with at least one of the nozzles input signal means whichcooperate so as to cause the position of the radial jet to change inaccordance with the applied input signal. A receiving chamber surroundsthe area where the fluid emanating from the nozzles impact and includesa pair of output openings which are spaced oppositely from the point ofimpact so as to produce equal signals at the output openings when thereis no input signal applied by way of the input signal means. The twooutput openings in the receiving chamber are effectively isolated byexhaust means.

Referring now to the drawing and more particularly to FIGURE 1 there isillustrated a push-pull amplifier in accordance with the presentinvention. As is therein shown, the amplifier 10 includes a housing 11having a pair of input tubes 12 and 13 connected thereto and alignedaxially along the axis a-b. Sources of fluid (not shown) are connectedto tubes 12-13 to provide fluid flow into housing 11. Also connected tothe housing 11 is a pair of input signal means such as the tubes 14 and15. Input signals are applied to these tubes from sources thereof (notshown) to affect the flow of fluid through the tubes 12 and 13. A pairof output tubes 16 and 17 are also connected to the housing and sense,in a pushpull manner, any variation in the signals applied to the inputsignal tubes 14 and 15. An exhaust tube 18 is connected to the housing11 and cooperates to dump any fluid not flowing through the output tubes16 and 17 and thereby isolates the output tubes. Further exhaust tubes 38' 3'9' are connected to the housing 11 and function to provideisolation between the input and output signals.

A better understanding of the apparatus in accordance with the presentinvention will be had by reference to FIGURES 2 through 4 which will nowbe considered in some detail. As is shown in FIGURE 2 the input tube 12terminates in a nozzle 21 having an orifice 22. The input tube 13terminates in a nozzle 23 having an orifice 24. The orifice 22 of thenozzle 21 is disposed at the output orifice of an input signal receivingchamber A while the orifice 24 of the nozzle 23 is disposed at theoutput orifice of an input signal receiving chamber B. It should benoted that the output orifices of the chambers A and B are arrangedconcentrically with the output orifices of the nozzles 21 and 23respectively and thereby form a second pair of nozzles.

The remainder of the housing 11 is utilized as a receiving chamber C.The receiving chamber C is divided into output signal chambers 31 and 32and isolating exhaust chambers 33, 38 and 39. The output signal chamber31 is separated from the exhaust chamber 38 by a wall member 26 havingan aperture 27 therein while the output signal chamber 32 is separatedfrom the exhaust chamber 39 by a wall member 28 having an aperture 29therein. The output signal chamber 31 is further separated from theexhaust chamber 33 by a wall member 34 having an aperture 35 thereinwhile the exhaust chamber 33 is separated from the output chamber 32 bya wall member 36 having an aperture 37 therein. The exhaust chambers 38and 39 are vented to atmosphere by ports 38' and 39' respectively. Itcan be seen by reference particularly to FIGURE 2, that the two outputtubes 16 and 17 are effectively isolated one from the other by the twowalls 34 and 36 and the exhaust chamber 33 and from the input signalreceiving chambers by the exhaust chambers 38 and 39.

As is illustrated in FIGURE 2, in the absence of input signals appliedto the input signal tubes 14 and 15, the fluid power jets applied to thetubes 12 and 13 pass inwardly into the housing 11 as is illustrated bythe arrows 20-30 and meet in the exhaust chamber 33 and impact therein.At the point of impact a radial jet or cone 40 is formed as isillustrated. Assuming that the power jets 20 and 30 are equal in theircharacteristics, the radial jet 40 would be located at the exact centerof the exhaust chamber 33. Under these circumstances the output signalsexperienced in the output chambers 31 and 32 and appearing at the outputtubes 16 and 17 would be identical as is indicated by the arrows 41 and42 and there would be no differential therebetween. This being the casethere would be effectively zero output signal from the push pullamplifier of the present invention. In the event that some differencedid exist, as a result of manufacturing or operational tolerances forexample, between the output signals 41 and 42, under normal operatingconditions and in the absence of input signals at the input tubes 14 and15, either the signal 20 or the signal 30 would be adjusted so as tocause the output signals at' output tubes 16 and 17 to be substantiallyequal. Input signal information may be applied to input signal tubes 14and or either of them or alternatively the power jets and applied totubes 12 and 13 may be changed by way of introducing a variation in thesignal if such is desired. Typically however, inputsignals will beapplied to the input signal receiving chambers A and B by applying themto the input tubes 14 and .15.

By reference now to FIGURE 3 it is illustrated schematically what occursupon the application of an input signal to the input tube 14. Underthese circumstances an input signal is now experienced in the inputsignal receiving Chamber A which signal causes fluid flow to be directedthrough the orifice from Chamber A surrounding the nozzle 21. This fluidflow forms a pressure surrounding the jet 20 emanating from the nozzleorifice 22. Under these circumstances the diameter of the jet 20 isslightly constricted thus increasing the momentum flux thereof. Since nochange has been imparted to the input power jet 30, the balance pointbetween the jets 20 and 30 is caused to move toward the right as isillustrated at in FIGURES 3. Such movement of the balance point occurssince the momentum flux of the input jet 20 plus the momentum flux ofthe input signal applied to the input signal receiving Chamber A isgreater than the momentum flux of the input jet 30. As a result of themovement of the radial jet 40 toward the right the output signalemanating from the output tube 17 is larger as is illustrated at 42'than is the output signal from the tube 16 as is illustrated at 41. Thusthere is a difference between the output signals 41' and 42' and thedifference therebetween is the output signal from the push-pullamplifier in accordance with the present invention.

If an input signal is applied to the input tube 15 as is illustrated inFIGURE 4, then exactly the reverse of that which was described withrespect to FIGURE 3 occurs. That is, the momentum flux of the input jet30 is increased relative to the momentum flux of the input jet 20 thuscausing the radial jet 40 to move toward the left and to therebyincrease the output signal 41 as compared to the output signal 42" as isshown. It should, of course, be understood that although the radial jet40 is shown completely in output chambers 31 and 32 in FIGURES 3 and 4,respectively, it may occupy any position within the receiving chamber Cwhich may be dictated by the relative dicerence between the momentumflux of the input streams 20 and 30 as afliected by input signalsapplied to the input signal receiving chambers A and B. It should alsobe understood that in each case any flow which does not appear at theoutput tubes 16 and 17 would of course be exhausted through the exhausttubes 18, 38' and 39' to atmosphere or to a fluid sump as the case mayrequire.

As will be recognized by those skilled in the art, the fonegoingdescription of a push-pull amplifier in accordance with the presentinvention utilizes the principles and techniques of the direct impacttype proportional amplifier. It should also be understood that withoutdeparting from the spirit or scope of the present invention thetechniques and principles of the transverse impact proportionalamplifier may also be utilized. Such an embodiment in accordance withthe present invention is illustrated in FIGURE 5 to which reference ishereby made. As is therein illustrated the power jet 50 is appliedthrough a nozzle 51 into an input signal receiving chamber 52. An inputsignal may be applied through an input nozzle or tube 53 as isillustrated by the arrow 54 so as to be in a transverse impactrelationship with the input signal 50 applied through the nozzle 51.Also an input power jet 60 may be applied through a nozzle 61 into aninput signal receiving chamber 62. An input signal may be appliedthrough the input nozzle or tube 63 as is illustrated by the arrow 64 soas to be in a transverse impact relationship with the power jet 60.Under these conditions the axial position of the power jets 50 and 60may be changed as a result of the transverse impact of the signals 54and 64 therewith in the input receiving chambers 52 and 62. The axialposition of the power jets 50 and 60 being thus changed affects themomentum flux of these power jets and thus causes the radial jet 70 tomove within the receiving chamber in accordance with the relativestrength of the momentum flux of the power jets 50 and 60 as abovedescribed. As the radial jet 70 positions itself in accordance with therelative momentum fluxes of the power jets 50 and 60 the output signals71, 72 appearing at the output tubes 68 and 69 also change. The systemagain is arranged in such a manner that under those circumstanceswherein there is no input signals 54 and 64 the power jets 50 and 60being equal in characteristics, the radial jet 70 is positioned in sucha manner that the output signals 71 and 72 are substantially equal thuspresenting no differential signal therebetween. In a system of the typeillustrated in FIGURE 5, the two input signal receiving chambers 52 and62 are exhausted as is illustrated at 55 and 65 respectively.

It should again be understood that the input signals 54 and 64 may beapplied separately or simultaneously and have any particular magnitudewhich is desired for the particular application under consideration. Aswas above indicated under these circumstances the radial jet 70positions itself in accordance with the difference between the momentumfluxes of the two jets 50-60 as aflected by these input signals.

There has thus been disclosed and described two embodiments of aproportional push-pull summing amplifier utilizing the impact principlesand techniques of the prior art. Although a detailed description andillustration has been given such is to be taken by way of explanationand illustration only and is not to be taken as a limitation upon thescope of the present invention as defined in the appended claims.

What is claimed is:

1. Pure fluid push-pull summing amplifier comprising:

(A) first and second axially aligned spaced apart input orificesarranged to cause fluid emanating therefrom to impact along the axis ofsaid orifices and form a radial jet;

(B) first input signal means cooperatively arranged to vary thecharacteristics of fluid emanating from said first orifice to change theposition of said radial jet proportional to variations imparted to saidfluid;

(C) a receiving chamber surrounding the area where fluid emanating fromsaid orifices impacts;

(D) first and second output openings communicating with said receivingchamber,

( 1) said output openings being spaced oppositely from the point ofimpact on said axis to produce substantially equal signals at saidopenings in the absence of an input signal at said first input signalmeans; and

(E) exhaust means connected to effectively isolate said output openingsfrom each other.

2. Pure fluid amplifier as defined in claim 1 which further includessecond input signal means cooperatively arranged to vary thecharacteristics of fluid emanating from said second nozzle.

3. Pure fluid amplifier as defined in claim 2 in which said exhaustmeans includes first, second and third exhaust chambers eflectivelyisolating said first and second output openings from each other and fromsaid first and second input signal means respectively.

4. Pure fluid amplifier as defined in claim 3 wherein said first andsecond input signal means is arranged not to change flow direction offluid emanating from said nozzles.

5. Pure fluid amplifier as defined in claim 3 wherein said first andsecond orifices are defined by first and second input nozzles and saidfirst and second input signal means include fluid flow directing meansconnected to receive signal fluid and direct it into contact with saidfluid emanating from said first and second nozzles.

6. Pure fluid amplifier as defined in claim 5 wherein said first andsecond input signal fluid flow directing means are second and thirdorifices surrounding said first and second nozzles respectively.

7. Pure fluid amplifier as defined in claim 5 wherein said first andsecond input signal means is a pair of nozzles each having an axisdisposed transversely of the axis of said first and second inputorifices.

8. Pure fluid amplifier as defined in claim 5 wherein said first andsecond output openings are spaced approximafely equal distances inopposite directions from the center of said receiving chamber.

9. Pure fluid amplifier as defined in claim 8 wherein said receivingchamber includes first and second output chambers, said first and secondoutput openings being in communication With said first and second outputchambers respectively, and said first exhaust chamber is disposedbetween said first and second output chambers.

10. Pure fluid amplifier as defined in claim 9 which further includes afirst input signal receiving chamber having said first nozzle orificedisposed therein and said first input signal means including an openingcommunicating with said first input signal receiving chamber, and asecond input signal receiving chamber having said second noZZle orificedisposed therein and said second input signals means includes anopeningcommunicating with said second input signal receiving chamber.

11. Pure fluid amplifier as defined in claim 10 which includes a housingand in which said input signal receiving chambers, said output chambersand said exhaust chambers are defined by substantially parallel spacedapart wall members disposed in said housing, each wall member definingan aperture therein, said apertures being aligned and axially disposedalong the axis of said nozzles.

12. Pure fluid amplifier as defined in claim 11 wherein the aperture insaid wall members defining said first and second input signal receivingchambers each defines effectively a nozzle orifice concentricallydisposed with respect to said first and second input nozzle orificesrespectively.

References Cited UNITED STATES PATENTS 3,272,215 9/1966 Buornsen et al137-81.5

3,279,489 10/1966 Buornsen et a1 13781.5

3,285,263 11/1966 Buornsen et al 137-815 3,323,532 6/1967 Campagnuolo137-815 M. CARY NELSON, Primary Examiner.

WILLIAM R. CLINE, Assistant Examiner.

